Looks like there's little left of the chassis except the cockpit. Was it ever given a body?

cool picture (courtesy of MatraPassion).No, I don't think it was ever given a body, or even driven.

The middle seat was sacrificed in favour of extra space for the engine, and reinforcement of the chassis bahind the the seats.

My guess would be that the intended body would look somewhat similar to the 180hp Murena 4S - with extra scoops added, to cool both engine AND the brakes, which were mounted on the ZF gearbox, rather than adding weight to the wheels.

Quite a substancial part of the chassis is in fact there, but everything over and behind the engine obviously had to go - to be replaced by something else later (which never happened, as far as I know)

The wheel-base has grown quite a lot , but considering the Murena is such a small car, its a good job fitting a V12 longitudinally there ! :-)

And, Matra have previously done a great job, designing a body for an extended wheelbase version (the Bagheera U8)

Now, in the 1980'ies, Matra produced the V6 (turbo) for Ligier and /or Shaddows - without turbo that would have been a great engine to fit in a Murena.